Gov. Martin O'Malley is proposing a measure to help develop offshore wind that is very similar to a bill that fell short last year, but this time he's finding a more favorable climate in the Maryland General Assembly.

The measure that passed 30-15 has been a priority for Gov. Martin O'Malley, who pushed unsuccessfully for the bill for two years before finally finding success with a scaled-back proposal. The bill was already passed this session by the House of Delegates, which will only have to sign off on several small changes the Senate made before sending it off to O'Malley to sign.

The Democratic governor has noted challenges clearly remain to get the project off the ground. Still, he has expressed confidence the measure will put Maryland on track to partner with neighboring states to lead an offshore wind project off the East Coast.

"It's an affirmative step by the Legislature, so it allows us to go out and look for the art of the deal that will get these things built," O'Malley said in a brief interview after the Senate vote.

All the supporting votes came from Democrats. Three Democrats joined 12 Republicans in opposing the bill.

Environmental groups cheered the vote. Mike Tidwell, executive director of the Chesapeake Climate Action Network, described it as a significant victory for clean energy.

"This bill is to offshore wind power in the Mid-Atlantic what the early railroads were to American transportation," Tidwell said in a statement. "It's a driver of innovation that will create jobs, enhance our economy, improve public health and protect the climate."

The proposal, which will take years to develop, would increase monthly electricity bills for ratepayers by an estimated $1.50 a month. Commercial ratepayers could see increases of up to 1.5 percent.

Republican critics denounced the measure for increasing electricity bills in order to develop the world's most expensive forms of electricity.

"This is not the path," said Sen. E.J. Pipkin, R-Cecil. "This is a private enrichment bill. Our citizens deserve better than this from us, and that's why, ladies and gentlemen, I believe this is the dumbest idea ever."

But supporters underscored ratepayers would only pay for energy they receive, not infrastructure involved in the project. Ratepayers also would only pay once they started receiving electricity from offshore wind.

"Maryland ratepayers, Maryland taxpayers, have absolutely no connection to this project except for a purchase of power," said Sen. Thomas Middleton, D-Charles. "That's all we're purchasing."

The Public Service Commission has a year to develop regulations. The earliest a developer could propose is project is July 2014. The O'Malley administration estimates 2017 is the earliest a project could be up and running.

A scaled-back version of O'Malley's initial bill passed the House of Delegates last year, but stalled in the Senate Finance Committee. This year, Senate President Thomas V. Mike Miller moved a member of the panel to another committee to secure the vote needed to get the measure to the Senate floor for a debate.